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Re: [css-animations] When/how are keyframe values computed?

From: Sylvain Galineau <galineau@adobe.com>
Date: Mon, 11 Aug 2014 17:29:41 +0000
To: Tab Atkins Jr. <jackalmage@gmail.com>
CC: Lea Verou <lea@verou.me>, "L. David Baron" <dbaron@dbaron.org>, "<www-style@w3.org>" <www-style@w3.org>
Message-ID: <AD328791-741E-4CAA-9112-DE9ADD68C1E8@adobe.com>

On Aug 11, 2014, at 9:36 AM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:

> On Mon, Aug 11, 2014 at 9:12 AM, Sylvain Galineau <galineau@adobe.com> wrote:
>> On Aug 10, 2014, at 9:55 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
>>> I don't know what you mean by this.  The "50%" is 50% progress through
>>> the timing function.  You can tweak that to your heart's content, and
>>> make the switch happen anywhere from the beginning to the end.
>> 
>> Well, I don't know what you mean by this :) If the switch for non-animatable properties always occurs 50% through the timing function, how do I tweak it to happen anywhere? Negative animation-delay certainly let you drag it further to the beginning. But how do you push it to the end of the duration? Or do you mean something else?
> 
> Okay, something's going terribly wrong in one of our mental models, or
> one of our wording choices, if we can't understand each other here.
> 
> To adjust where the 50% point is, you just... change the timing
> function.  You can get the 50% point literally anywhere from start to
> finish by providing the appropriate cubic-bezier() function.  (Of
> course, using steps() is easier for actual start/end, but still.)
> 
> Maybe you're misunderstanding that by "make the switch happen
> anywhere", I mean "make the switch happen anywhere in the duration of
> the animation"?  It always occurs at 50% *progress*, but that can
> occur at any *time*, depending on your timing function.

OMG my understanding was so WRONG. I translated '50% of the timing function progress' to mean '50% of the time interval between start/end values' when instead if was '50% of the distance along the timing function curve'. 

Is that the door?
I'll show myself out. 
Received on Monday, 11 August 2014 17:30:12 UTC

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